1. Field of the Invention
The present invention relates generally to trouser-fly piece serging machines, and more particularly to an apparatus for serging a trouser-fly piece along its curved one longitudinal edge while forming the curved longitudinal edge by trimming at least a corner of the leading end of the trouser-fly piece substantially arcuately.
2. Description of the Prior Art
In general, trouser-fly pieces, as shown in FIG. 6, have a substantially arcuate corner at one end thereof which is trimmed to make a pair of trouser's appear sightly and not to provide a sense of discomfort for the wearer. In a sewing shop for mass-producing trousers, a continuous elongate fabric which is the same as the fabric of the trousers is folded zigzag along the length thereof and subsequently, the fanfolded elongate fabric is severed at opposite folded ends, thus forming a number of trouser-fly pieces at one time. However, since the trouser-fly pieces thus severed are stacked in alternating front-to-front and back-to-back confrontation to one another, an additional process is needed to overturn every other trouser-fly piece prior to the corner trimming process stated above.
With the forgoing difficulty in view, according to a known practice, trouser-fly pieces of an elongate rectangular shape are severed one at a time from a continuous elongate fabric. Then, the individual trouser-fly pieces are manually supplied to a serging machine having a trimming cutter. In this instance, each trouser-fly piece while being gripped by the operator is manually turned as it is advanced through a serging station of the serging machine, so that a corner of the leading end of the trouser-fly piece is trimmed into a substantially arcuate shape. Substantially at the same time, one longitudinal edge of the trouser-fly piece including the trimmed arcuate corner is serged with an overedge or serge stitching to avoid raveling. The known serging practice including manual turning of the trouser-fly piece is tedious and time-consuming, requires a great deal of skill and considerably lowers the serging efficiency. Furthermore, the trimmed arcuate corner is irregular in shape.
Trouser-fly pieces used in the serging operation shown in U.S. Pat. No. 4,152,996 have a substantially arcuate corner at the leading end as they are previously trimmed along one longitudinal edge. As each of the trouser-fly pieces is advanced toward a serging station, the curved longitudinal edge including the arcuate corner is gradually pulled toward the opposite straight edge to form a longitudinal pucker or fold of an inverted U-shape. The fold is maintained until the trailing end of the trouser-fly piece passes through the serging station. With this transverse pulling of the curved longitudinal edge, a line of overedge or serge stitches can be formed on the curved longitudinal edge. However, owing to this transverse pulling process, the known serging machine cannot operate at high speeds. Furthermore, depending upon the material and thickness of a fabric forming the trouser-fly piece, the transverse pulling may be performed inaccurately with the result that an overedge or serge stitching does not conform to the shape of the curved longitudinal edge and makes the trouser-fly piece appear unsightly.